The use of fly ash in building materials diverts millions of tons of ash from the landfills each year, increases the constructability and durability of concrete and brick, partially replaces energy-intensive Portland cement, and is recognized by the U.S. Green Building Council’s LEED rating system as a post-industrial recycled material.
On the other hand, environmentalists question whether the industry has enough testing data to conclusively determine that this byproduct of power-producing coal combustion is environmentally safe…..   Read more

from GreenBuilder Magazine.